A number of surgical devices may be used to develop a surgical space within a body. For example, blunt dissectors or soft-tipped dissectors may be utilized to create a dissected space which is parallel to the plane in which the dissectors are introduced into the body.
More recently, surgical devices including an inflatable balloon have been used to develop an anatomic space. Such devices typically include an elongate shaft or obturator for tunneling into the body with the balloon attached to it. The balloon is generally collapsed initially, for example by gathering the balloon about the shaft, and is secured to the shaft by a tubular sheath or cover. The tunneling shaft with the deflated balloon thereon is introduced into the body and directed to a desired location. Once the desired location is reached, the balloon is deployed by inflation to develop the anatomic space, generally causing dissection along a natural plane within the tissue structures.
The balloon generally comprises two similarly shaped panels that are heat sealed, sonic welded or otherwise substantially fused together along their outer edges, creating a substantially fluid tight seam around the balloon. Although the material comprising the balloon panels is generally flexible, the material may become stiff and/or abrasive along the seam. During tunneling or when the balloon is deployed, an external seam may move along the tissues in the anatomic space being developed, potentially causing tissue trauma, particularly in sensitive tissues, and/or resulting in undesired bleeding in the space.
More particularly, in relation to laparoscopic procedures, surgical devices have been developed that permit visualization during tunneling as well as during development of the anatomic space. Such devices typically include a tunneling shaft, an inflatable balloon, and a laparoscope. The tunneling shaft comprises a substantially rigid tubular member having open proximal and distal ends, defining a passage adapted to receive a laparoscope therein. The balloon is generally formed from substantially transparent material, thereby allowing observation through the balloon wall. The distal end of the tunneling shaft may be inserted through a proximal end of the balloon into the interior of the balloon. Similar to other tunneling devices, the balloon is initially collapsed around the tunneling shaft and may be covered by a sheath.
The distal end of the tunneling shaft generally includes a lip partially obstructing the open distal end. The lip may be formed by providing a rounded tip on the distal end of the shaft and cutting away an angled section of the tip, for example at a forty five degree angle. The lip prevents a laparoscope inserted into the tunneling shaft from extending beyond the distal end of the shaft.
During tunneling, a laparoscope inserted into the tunneling shaft may be positioned for focus and used to observe the progress of the device, the transparent balloon wall allowing observation through the open distal end of the tunneling shaft. Once the desired location is reached, the balloon is inflated. During inflation, the distal end of the tunneling shaft and laparoscope may be moved around within the balloon to view the space being developed, to observe tissue dissection, and to identify tissue structures.
One problem with such devices is that the lip on the tunneling shaft may result in a sharp distal edge. This sharp edge may contribute to tissue trauma when the tunneling shaft is introduced into a body, and/or when the tunneling shaft is moved to observe the anatomic space being developed. The sharp edge may also damage or puncture the balloon, possibly requiring removal and replacement of the device.
In addition, the lip may substantially obstruct the field of view of the laparoscope. Although the tunneling shaft often comprises substantially transparent material in order to transmit light, distortion through the walls may impair peripheral visualization. Thus, the most effective field of view through the laparoscope is generally through the open distal end of the tunneling shaft. Because the lip partially blocks the distal end, however, the lip often obstructs the axial field of view. For this reason, such devices often employ an angled rather than a straight laparoscope, providing visualization at an angle out the open distal end, rather than in an axial direction. Thus, to fully view the tissues being dissected, the tunneling shaft may have to be rotated axially, which may be disfavored in some procedures.
Accordingly, there is a need for an apparatus and method for developing an anatomic space which provides improved visualization during tunneling and subsequent space development.
In addition, there is a need for a laparoscopic apparatus and method for developing an anatomic space which substantially minimizes tissue trauma during tunneling and development of the space, thereby reducing bleeding that may obscure the field.